The present invention is related to a damping and muffling structure for EL device, and more particularly to a damping and muffling structure which is made of de-static material for quickly removing the charge so as to achieve damping effect and minify or even eliminate the vibration and noise.
A conventional electro luminescent cell (EL cell) is a thin sheet and mainly used as backlight cell of PDA, mobile phone, etc. FIG. 6 shows a conventional EL cell composed of a transparent substrate 81, a front electrode layer 82, a lighting layer 83, an inducing layer 84, a back electrode layer 85 and an insulating layer 86. By means of a driving circuit, an AC voltage is applied to the front and back electrode layers 82, 85 to make the lighting layer 83 emit light.
Due to AC electric field, a lighting particle 831 of the lighting layer 83 are energized and vibrated to emit noise. This affects the quality of the EL cell.
In order to solve the problems of vibration and noise of the lighting layer 83 of conventional EL cell, generally the EL cell is backed to increase the thickness thereof so as to minify the vibration and noise. Alternatively, the EL cell is tightly attached to the circuit board to reduce vibration and noise.
However, the EL cell applied to small-size electronic products such as mobile phones is limited in thickness specification. Therefore, the backing will lead to excessive thickness. On the other hand, the EL cell can be attached to the circuit board to reduce over 60% noise. However, it is difficult to assemble the module and the use of double-face tape will lead to increased cost.
It is therefore a primary object of the present invention to provide a damping and muffling structure for EL device. The damping and muffling structure includes a damper for conducting the charge concentrating around the bus bar so as to minify or even eliminate the vibration and noise caused by AC electric field.
According to the above object, the damping and muffling structure of the present invention includes a transparent substrate, a transparent front electrode layer, a lighting layer, an inducing layer and a back electrode layer which are sequentially overlaid on the transparent substrate. The lighting layer, inducing layer and back electrode layer are enclosed by a packaging layer. A bus bar is disposed on one side of the front electrode layer. The bus bar and the back electrode layer are connected to a driving circuit which via AC voltage drives the lighting layer to emit light.
A damper made of de-static material is disposed on one face of the packaging layer distal from the front electrode layer. An insulating layer is disposed between the damper and the back electrode layer. The damper has an area sufficient for covering the bus bar of the front electrode layer. The damper is connected to a grounding pole of a driving circuit for quickly removing the charge so as to achieve damping effect and minify or even eliminate the vibration and noise caused by AC electric field.